The present invention relates to the field of implantation methods. Preferably, the invention relates to the field of ophthalmology and to the use of medical devices in ophthalmologic surgery. In a particularly preferred embodiment, the present invention relates to methods and procedures for inserting implants into the eye.
Artificial intraocular lenses are widely used to replace the human crystalline lens of the eye. The human crystalline lens is a living transparent structure composed primarily of protein having a thickness of about five millimeters and a diameter of about nine millimeters. The lens is suspended behind the iris by zonula fibers that connect the lens to the ciliary body. A lens capsule surrounds the lens; the front portion of the capsule generally referred to as the anterior capsule and the back portion generally referred to as the posterior capsule.
The term xe2x80x9ccataractxe2x80x9d refers to the opacity of the lens of the eye. There are a variety of types of cataracts and for most cataracts, surgical intervention is required to remove and replace the lens with an artificial intraocular lens.
The transparency of the lens depends on the physiochemical state of the lens proteins. These proteins, like the proteins of other organs, are sensitive to changes in the properties of their surrounding fluid. Changes in the concentration of dissolved salts, in the osmotic pressure, in the pH or in the enzyme activity of the surrounding fluid can alter the properties of the lens proteins. Also, like other organs, changes to the proteins of the lens occur with age. A common type of cataract that occurs in elderly people is known as a senile cataract. This type of cataract has no known etiology and none of the forms of cataract produced experimentally to date closely resemble the senile cataract.
Artificial intraocular lenses generally comprise an optical region and a support, or haptic, to facilitate positioning and centering of the intraocular lens within the eye. Intraocular lenses have been made from a number of different materials. For example, hard lenses have been prepared from polymethylmethacrylate (PMMA) and optical glass while flexible lenses have been prepared from silicone, poly HEMA (polyhydroxyethylmethymethacrylate), acrylics, collagen, and combinations thereof. Flexible lenses have the advantage that they can be folded or otherwise deformed prior to implantation to reduce the overall size of the lens during the artificial lens implantation procedure.
There are a number of procedures and devices that have been developed for the removal of the natural lens followed by the insertion of an artificial lens. The extraction procedure can generally be categorized as intracapsular (i.e., where the lens is removed together with the lens capsule) or extracapsular (such as where a portion of the anterior capsule is circularly removed (capsulorhexis) and the posterior capsule is left intact).
Presently, phacoemulsification is a widely used method for the removal of diseased or damaged natural lens tissue. The phacoemulsification process generally employs a small incision typically of about 2 millimeters (mm) to about 4 mm in length (but potentially as small as 1 mm) through the cornea and a probe is used to ultrasonically break apart and remove the crystalline lens through the capsulorhexis.
There are a number of intraocular lens injectors that have been described in the literature to position a deformable artificial intraocular lens in the eye. These injectors use an incision of about 2 mm to about 4 mm, the incision size most frequently used in most phacoemulsification procedures. A larger (about 4 mm to about 5 mm) capsulorhexis incision, also used in phacoemulsification procedures, is used to position the lens without requiring elongation of the incision during the injection process.
U.S. Pat. No. 4,681,102 to Bartell discloses one type of device to implant an intraocular lens through a small incision. The injector comprises a load chamber that is used to fold a soft intraocular lens into a shape having a smaller cross-sectional area than the original unfolded cross-sectional dimension of the lens. The load chamber comprises two hinged members that together define a generally cylindrical lumen. Each of the two members includes a flange that extends non-parallel to cylindrical members at a point of connection and permits manipulation of the cylindrical members from a first open position to a second closed position. The intraocular lens is inserted into the load chamber when the two members are in an open position. The flanges are advanced towards each other causing the two members to form the generally cylindrical chamber. As the two members advance towards each other, the intraocular lens that is inserted in the chamber is compressed to conform to the generally cylindrical shape of the members in the closed position. This device and those devices that include a rigid chamber for deforming the lens can damage the lens during the deformation process if the lens is not accurately and carefully positioned in the chamber.
A number of patents use a push-rod (also described in these patents as a pusher or piston-type device) to apply a force directly on a lens and to push the deformed lens from the device into the eye. For example, the loading chamber of Bartell (supra) is placed into a rigid injector portion fitted with a push-rod. The push-rod pushes the intraocular lens through a generally circular lumen of the loading chamber and into an injector nozzle. The pushing action of the push-rod can further damage the lens material and haptics before the lens is positioned in the eye.
U.S. Pat. Nos. 4,702,244 and 4,573,998 to Mazzocco discloses a push-rod type of device that functions similar to a plunger of a syringe to provide a hydraulic force on a lens. The device includes a chamber for containing the intraocular lens in an unstressed state and for orienting the lens in a prescribed orientation to facilitate lens placement within the eye. The plunger is used to exert a direct force on the lens or a direct force on liquid surrounding the lens, sufficient to deform the lens such that the optical zone is deformed to a substantially smaller cross-sectional diameter than the optical zone in an unstressed state. The device includes a means to expel the lens from the device for placement in the eye. The surgical device disclosed by Mazzocco requires the use of a direct force such as a hydraulic force or a pneumatic force to move the lens from its unstressed stated into a deformed position. In the embodiment that compresses the lens from an unstressed state to a stressed state, the lens is propelled toward a small opening at the end of a holding tube. As the lens approaches the opening it is folded back against itself and compressed to fit through the opening. The orientation of the lens in the device is not uniform, nor would deformation be consistent with each injection. Moreover, the hydraulic force would likely be quite high and this pressure is likely not practical for use in the internal aspects of the eye.
U.S. Pat. No. 5,468,246 to Blake discloses another type of intraocular lens injector that compresses the diameter of the intraocular lens by rolling the lens into a tight cylindrical tube that can be inserted into the eye through a small incision of about 2 millimeters to about 4 millimeters. This device also uses a push-rod-type device to apply a direct force to move the lens from the injector device into the eye.
U.S. Pat. No. 5,562,676 to Brady, U.S. Pat. No. 5,275,604 to Rheinish, U.S. Pat. No.5,474,562 to Orchowski, U.S. Pat. No. 4,919,130 to Stoy, U.S. Pat. No. 5,123,905 to Kelman and U.S. Pat. No. 5,616,148 to Eagles use an injector with a tapered or conical loading chamber to guide and fold the lens into a rigid lumen. These patents also use a push-rod to inject the lens from the lumen into the eye. A problem with these injectors is that the internally positioned push-rod is in direct contact with the lens assembly. This direct contact can result in distortion, bending or breakage of a trailing haptic. In addition, compressive forces on soft or fragile lens materials can tear the lens or destroy a haptic. In addition, during compression, the push-rod can catch or wedge a portion of the lens between the rigid lumen of the device and the push-rod mechanism.
There remains a need for a device for introducing a flexible implant, particularly fragile foldable lenses into the body without damaging that implant. In particular, there is a need for a device to implant a foldable intraocular lens into an eye without damaging the lens or the haptics during the implantation process.
This invention discloses insertor devices that employ a flexible compressible sleeve to deliver an implant into the body. In accordance with one embodiment of the invention, the invention relates to a sleeve supporting device comprising a substantially flexible hub having a first opening and a second opening and a lumen extending therethrough. The lumen is adapted to substantially conform to the shape of a sleeve.
In another embodiment, the invention relates to a device for loading an implant into an implant delivery apparatus. The device comprises an elastomeric holder having an exterior surface and an interior surface. The exterior surface is suitable for gripping and the interior surface is adapted to generally receive and conform to an exterior shape of the implant delivery apparatus.
In another aspect of this invention, the invention relates to a method for assembling an implant insertion device. The method comprises loading an implant into a sleeve where the sleeve has a first opening and a second opening. The method further comprises coupling the first opening of the sleeve to a first end of a hand-piece and securing the sleeve to the first end of the hand-piece with a deformable sleeve holder.
In yet another aspect, the invention relates to a system for loading an implant. The system comprises a flexible, compressible sleeve wherein the sleeve comprises a first opening and a second opening and a first lumen extending through the sleeve and further wherein the sleeve is prepared from a non-opaque material. The width of the first opening is larger than the width of the second opening. The system further comprises a sleeve holder prepared from a substantially flexible material and comprising a second lumen extending therethrough, wherein the second lumen is adapted to substantially conform to the shape of the sleeve.
In still another aspect of the invention, a system for introducing an implant into the body is provided comprising a flexible, compressible sleeve. The sleeve comprises a first opening and a second opening and a first lumen extending through the sleeve, wherein the sleeve is prepared from a non-opaque material. The width of the first opening is larger than the width of the second opening. The system further comprises a sleeve holder prepared from a substantially flexible material and comprising a second lumen extending therethrough, wherein the second lumen is adapted to substantially conform to the shape of the sleeve. An implant positioned within the first lumen is also included. In yet another aspect of the invention, a hand-piece having a first end is also included. The hand-piece is capable of coupling to and retaining the sleeve. In yet another configuration, the first end of the hand-piece comprises at least one circumferential barb.
In still yet another embodiment of the invention, the invention relates to a kit. The kit includes a flexible, compressible sleeve wherein the sleeve comprises a first opening and a second opening and a first lumen extending through the sleeve, where the sleeve is prepared from a non-opaque material. The width of the first opening is larger than the width of the second opening. The kit further comprises a sleeve holder prepared from a substantially elastomeric material and comprising a second lumen extending therethrough. The second lumen is adapted to receive and substantially conform to the shape of the sleeve. The kit further comprises an implant positioned within the first lumen and a hand-piece having a first end, the first end adapted to couple with the first opening of the sleeve.
Other embodiments are also possible without departing from the scope of the invention. Advantageously, the present invention provides devices and methods for use with an ophthalmologic insertor apparatus, various embodiments of which are described and illustrated below.